P0171 FIXED! (Bad TPS sensor)

[the padre]

I am posting this to help anyone else who struggles with a P0171 or P0174 lean condition code. My car is a 2003 S40. My symptoms included:
1) CEL code p0171 and p0174
2) Stall at acceleration after a stop and also stall after letting off the accelerator at low speeds
3) Hesitation at wide open throttle

After replacing my:
-MAF
-MAP (both)
-O2 sensors (both)
-Spark plugs, coils, and wires
-I also smoke tested for any vacuum leaks (there was one) but I still had my p0171 code.

I cleaned my throttle body and found that my throttle position sensor (TPS) was gunked up.

After replacing my TPS, and resetting the cel with my code reader, all problems have gone away.

Note: I highly recommend replacing your throttle body gasket if you take off your throttle body, as my gasket fell apart when I took it off. Also, I had replaced my MAF with a cheap part made in China, but experienced other problems. After switching to an OEM part, the issues went away.

Good luck!